1. Field of the Invention
This invention generally relates to portable tie-down devices attachable to anchor means, and more particularly to improvements in the means for demountably attaching the tie-down device to the anchor means.
2. Description of the Prior Art
An example of this type of tie-down device is disclosed in the attachment fitting illustrated in U.S. Pat. No. 2,962,245, issued on Nov. 29, 1960. The attachment fitting disclosed therein generally comprises a five-spoke dog type body structure and a four-spoke dog type body structure interconnected by a stud. A connecting sleeve is freely rotatably mounted on the stud and lies between the two body structures. Each body structure is similarly constructed and includes a body member having a plurality of engaging dogs such as parallel grooves with indentations in one side thereof to engage the spokes of a fixed anchor. A plurality of locking dogs provided on a spring urged collar lie in the grooves in the body structure to hold the anchor spokes in the indentation. The collar is moved away from the engaging dogs on the body structure to install the device and the engaging dogs are moved into position over the spokes and rotated until the spokes engage the aforementioned indentations. The collar is then released and the spring urges the locking dogs into the space between the engaging dogs, thus locking the spokes in the indentations in the body members. This prior art device has a number of disadvantages. Thus, a relatively large number of separate elements is required to make up the attachment fitting. Also, the collar is spring loaded and thus it may inadvertently permit the locking dogs to become disengaged from their respective grooves, permitting the attachment to "break free" from the anchor fitting during use.